The marginal division (MrD) is a neostriatum subregion that links the limbic system and basal nucleus of
Meynert; it is an important subcortical center that is involved in learning and memory. Alzheimer’s disease (AD) is a neurodegenerative
disorder and the most common cause of dementia in the elderly. AD clinically manifests as gradually progressive
cognitive decline with behavioral disorders. Prior to full dementia, AD patients typically experience a transient
state, i.e., mild cognitive impairment (MCI). Amnestic MCI individuals, but not all MCI individuals, frequently convert to
AD dementia. To specify whether and how the functional relationships between the MrD and other brain regions change
during AD, functional connectivity was assessed using resting-state functional MRI data and associated neuropsychological
tests in AD and MCI patients (amnestic-type). Compared with normal controls, a different decreased functional connectivity
pattern was observed between the MrD and caudate, the amygdala/parahippocampal region, the inferior frontal
gyrus, the superior temporal gyrus, and the cerebellum for AD/MCI patients. Moreover, the functional connectivity between
the MrD and the identified regions was significantly correlated with the neuropsychological scores among the MCI
and AD subjects. Our results suggest that the MrD functional network is disrupted during AD.